Intermittent drive mechanism



July 23, 1940. R. E. BASSETT, JR

.INTERMITTENT DRIVE MECHANISM Filed Nov. 12, 1938 drive is resilient. Preferably a rotating cam or which draws the pawl and dog into engagement the like is providedto movea driving pawl'in one with the ratchettwheel in such amannerthat direction and the pawl is returned by aspringand they will tend to be drawn into a line passing drives a ratchet wheel during its return-motion; through the pivot points of, the pawl and dog. It Still another object of' the inventionis to promay-be noted that the three pivot points are sub- 15 vide an intermittent drive mechanism including stantially equidistant fro m each other so that the a driving pawl and a dog to prevent. reverse rotapawl actuating arm forms one side of an equition in which a single resilient element holds lateral triangle circumscribed about the ratchet both the pawl and dog in operative engagement wheel. y v g t with a driven ratchet wheel. Accordingto one In operation,-a's the cam-l6 is driven it moves feature of the invention the resilient element may I the arm 24 and pawl 26 to the right, the conalso serve as the driving spring. struction being such thatthe'pawl is moved Other objects, advantages and novel features of slightlymore than the length of a single ratchet the invention will be apparent from the. following tooth. When-the arm 24 drops off the shoulder description when read in connection withjthe ac- I8 the spring 28 moves it to the left and the pawl 25 companying drawing in which: .turns the ratchet wheelcounterclockwise in an Figures 1. 2 and 3 are sectional views with parts amount equal to the le gth of one tooth. Nor-' in elevation of three forms of intermittent. drive mally the springaction' is very rapid to give the mechanism embodying the invention. ratchet wheel aquick movement but in the event V 30 The invention is illustrated as embodied in a the driven mechanism should jam the spring will 30 drive mechanism particularly. adapted for use yield so that no damage will be done. d with sequential controllers of the type more par- The mechanism of Figure 2 is substantially ticularly disclosed and claimed in my copending similar to thatof Figure l and for purposes of applications Serial Nos. 240,163 and 240,164, filed brevity corresponding parts have beenindicated November 12, 1938. As shown in Figure 1 it is .by the same reference numerals. In this con- A driving shaft I4 driven by a motor or the cam Hi, the arm being oscillated in the same 40 Patented July 23, 1940 d Y I 2,208,831-

UNITED STATES PATENT 1 OFFICE INTERMITTENT DRIVE MECHANISM Rex Earl Bassett, Jr., South Bend, Ind., assig'nor to Bendix Home Appliances, Inc., South Bend, Ind., a corporation of Delaware Application November 12, 1938, Serial No. 240,057

This invention relates to intermittent drive rection by the earn it and is urged in the othermechanism and more particularly to mechanism direction against the; cam by leaf spring 28 for converting continuous rotary movementto -mounted in'apost 30. step-by-step rotary movement. The ratchet wheel is prevented from rotating One of the objects ofthe invention is to provide backwards by a dog 32 pivoted to the plate l2. and a simple compact mechanism which willeflicientextending substantially parallel .to the pawl. 26 1y convert continuous rotary motion into interand having a tooth engaging the ratchet wheel at mittent rotary motion. a point diametrically opposite the point of en- Another object of the invention is to provide gagement of thetooth on pawl 26. The dog 32 m an intermittent drive mechanism in which the and pawl 26 are connected by a tension spring 34 0 mounted in a casing Ill adapted to contain any .struction the driving'and driven-shafts are arother mechanism to be driven as well as a drivranged coaxiallyiend to end so that the cam. I5 ing motor or the like if desired. A transverse. and ratchet. wheel 22 are arranged side by side plate I2 is mounted in the casing and serves as a and rotate about a common axis. The arm 24 is support for the drive mechanism. formed with'a projecting finger 36 engaging the like extends through the plate'l2'andcarries-admanner as described above in connection with 'jacent thereto a cam l6 formed. with a gradual Figure 1. rise substantially throughout its circumference In the form of Figure 3 there is shown a casing and an abrupt drop or shoulderat IS. The shaft 40 having a transverse partition plate 42 through 45 to be driven is shown at 20 as provided with a which there extends a driving shaft not shown. squared portion on which a'ratchet wheel 22 is A cam 44 is mounted on the driving shaft ad-' mounted. f jacent the plate 42 and a. driven shaft 46 coaxial In order to drive the ratchet wheelan arm 24 with the driving shaft carries a ratchet wheel is' provided pivoted to the plate l2 at apoint re- 48 lying close to the plate on the side opposite mote from the drive shaft l4 and having'its free t am. Y end engaging the ratchet 16. A pawl 26 is An arm 50 ispivoted on the plate 52 and has a pivoted to the arm24 and is provided with a pawl 54 pivoted to its free end at 56. A dog 58 tooth engageable with. the teeth on the ratchet is pivoted to the plate at 60 and lies substantially wheel 22. "The arm 24 will'be moved in onediin 'alinement with the pawlf54. The pawl and 55 it is not intended to limit tion tothe exact forms shown nor otherwise than dog are formed at their free ends with teeth'engaging the teeth of ratchet wheel 48. It will be noted that the pivot points 52, 56 and 60 are spaced substantially equidistantly and are substantially equidistant from the axis of the driving and driven shafts.

The arm is formed with a finger 62 extending through an opening in the plate 42 and engaging the periphery of the cam 44. This finger is held in engagement with the cam and the pawl and dog are urged against the ratchet wheel by a common tension spring 64 connected to pins 66 on the pawl and dog and lying in a line above the line between pivot points 56 and 60. Thus the tension of the springtends to tilt the pawl and dog into engagement with the wheel, the spring attempting to aline itself with the pivots 58 and Gil.

As the cam rotates it swings the arm 50 to the left, stretching the spring 64. When the finger 62 drops off the shoulder on the cam the spring will return arm 50 to the right, the pawl engaging the ratchet wheel and turning it an amount equal to the length of one tooth.

While several embodiments of the invention have been shown and described it will be apparent that changes might be made therein and the scope of the invenby the terms of the appended claims.

All of the subject matter described above is fully disclosed in my application Serial No. 141,078 filed May 6, 1937.

What is claimed is:

1. In apparatus of the type described, the combination including a ratchet wheel, a pawl having a wheel engaging portion for imparting movement thereto in a predetermined direction, a dog having a wheel engaging portion for preventing movement of the wheel in the opposite direction, said pawl and dog being mounted at points substantially diametrically opposite each other, resilient means tending to move said wheel engaging portions into coincidence with a line passing through said pivot points, and means including an arm pivotally mounting said pawl intermediate its ends and pivoted at one end, a rotatable cam adapted to bear against the other end of said arm, second resilient means adapted to maintain said arm and cam in operative relationship, and means for rotating said cam whereby said wheel is given a step-by-step movement through said pawl and ratchet mechanism.

2. A pawl and ratchet mechanism including'a ratchet wheel, a pawl for imparting one way movement thereto, .a dog for' preventing movement thereof in a reverse direction, and dog being pivotally mounted at points substantially diametrically opposite each other and having wheel engaging portions located substantially'opposite each other on lines substantially tangential to the wheel and passing through the pivot points, and resilient means tending to move said pawl and dog tact with the wheel.

3. In apparatus of the type described, the combination including a ratchet wheel, 'a pawl having a wheel engaging portion for imparting movement thereto in a predetermined direction, a dog having a wheel engaging portion for preventing movement of the wheel in the opposite direction, said pawl and dog being mounted atpoints substantially diametrically op- "ll fposite each other, resilient means tending tosaid pawl toward each other and main- -tain the wheel engaging portions thereof in conpivotally move said wheel engaging dence with 'a line passing through said pivot points, and means adapted to impart a slight oscillatory movement to said pawl and its mounting for moving said wheel. I

4. In apparatus of the type described, the combination including a ratchet wheel, a pawl having a wheel engaging portion for imparting movement thereto in a predetermined direction,

is rotated.

5. In apparatus of the type described, the combination including a ratchet wheel, a pawl having a wheel engaging portion for imparting movement to said wheel'in a predetermined direcportions into coincition, a dog having a wheel engaging portion for preventing movement of the wheel in the opposite direction, said pawl and dog being mounted at points substantially diametrically, opposite each other, resilient means tending to move said wheel engaging portions into coincidence with a line passing through said pivot points for maintaining them in engagement with said wheel, and means including an arm pivotally mounting said pawl at one end and pivotally mounted at the other, a rotatable cam mounted coaxially with said wheel and bearing against an intermediate portion of said arm, and second resilient means adapted .to maintain said arm and cam in operative relationship, and means for rotating said cam whereby said wheel is given an intermittent step-by-step movement through said pawl and ratchet mechanism.

6. An. actuating mechanism for a ratchet wheel rotatable about a fixed axis, including a pawl pivotally mounted upon -a member mounted for pivotal movement about a fixed point for moving said wheel in a predetermined direction, adog mounted for pivotal movement about a fixed point for preventing. movement of said wheel in an opposite direction, the wheel engaging portions pivot point of said member being 50 located with respect to each other that a single resilient means under tension mounted on said pawl and dog imparts movement of all said members toward the axis of said wheel.

'7. An wheel rotatable about a fixed axis including, in combination, a pawl pivotally mounted upon an arm mounted for pivotal movement about a fixed point formoving said wheel-in a predetermined direction, a dog mounted for pivotal movement about a fixed point for preventing movement 0! said wheel in an opposite direction, acam rotatable about said axis, and single resilient means under tension mounted on said pawl and dog for maintaining said pawl and dog in engagement with the ratchet wheel and said arm in enof said pawl and dog and the actuating mechanism for a ratchetv aaoaaai I 3 point located at a distance greater than the radlotally mounted on said arm and engageable with of the wheel from said axis, said arm having the ratchet wheel to rotate it in one direction, a length equal to one side of an equilateral tria plvotally mounted dog engaaeabie with the angle circumscribed about the wheel and simratchet wheel to prevent movement thereof in 5 ilarly located with respect to said wheel, a pawl the other direction, resilient means enaasingthe 8 pivotally secured to the free end or said am and pawl and dog to urge them toward the ratchet having a length approximately half that oi the wheel, a ca engaging said ;-.-mand means to 10 a fixed pivot point located at the remaining apex 10. In apparatus of the type w the l pawl and dog for maintaining them in engage mounted adjacent the ratchet wheet, a wi 15 movement to said wheel through the pawl said tion, a pivotaily mountw dog enaageable with last named means comprising a cam positioned the ratchet wheel to prevent movement therecoaxially with the ratchet wheel and engaging of in the other direction, resilient means engag said arm intermediate its length and means for ing the pawi and dog to urge them toward the rotating the cam. ratchet wheel, a cam coaxial with the ratchet 2o 9." In apparatus or the type described, the comwheel and engaging said arm and means to robination 01' a ratchet wheel, an arm plvotally tate the cam to cause the arm tooscillate. mounted adjacent the ratchet wheel, a pawl piv- EARL B 

